Mapping transform of query plan model in grid database based on Petri net
基于Petri网的网格数据库查询计划模型的映射转换

In Grid Database, the schedule policy of query plan based on Directer Acyclicgraph (DAG) is mainly adopted, which overlooks the data relation between subquery and nodes. This paper described the deficiency of schedule policy based on DAG, promised a new model NSN based on Petri Net, which can describe the relation of subquery and node, and gave transformation rules and schedule arithmetic from DAG to NSN, and finally carried out experiments to prove the advantage of NSN over DAG in assigning subquery to node.